linux/drivers/gpu/drm/drm_dp_dual_mode_helper.c
Imre Deak 7eb2c4dd54 drm/i915: Fix LSPCON TMDS output buffer enabling from low-power state
LSPCON adapters in low-power state may ignore the first I2C write during
TMDS output buffer enabling, resulting in a blank screen even with an
otherwise enabled pipe. Fix this by reading back and validating the
written value a few times.

The problem was noticed on GLK machines with an onboard LSPCON adapter
after entering/exiting DC5 power state. Doing an I2C read of the adapter
ID as the first transaction - instead of the I2C write to enable the
TMDS buffers - returns the correct value. Based on this we assume that
the transaction itself is sent properly, it's only the adapter that is
not ready for some reason to accept this first write after waking from
low-power state. In my case the second I2C write attempt always
succeeded.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105854
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180416155309.11100-1-imre.deak@intel.com
2018-04-18 16:33:14 +03:00

525 lines
15 KiB
C

/*
* Copyright © 2016 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <drm/drm_dp_dual_mode_helper.h>
#include <drm/drmP.h>
/**
* DOC: dp dual mode helpers
*
* Helper functions to deal with DP dual mode (aka. DP++) adaptors.
*
* Type 1:
* Adaptor registers (if any) and the sink DDC bus may be accessed via I2C.
*
* Type 2:
* Adaptor registers and sink DDC bus can be accessed either via I2C or
* I2C-over-AUX. Source devices may choose to implement either of these
* access methods.
*/
#define DP_DUAL_MODE_SLAVE_ADDRESS 0x40
/**
* drm_dp_dual_mode_read - Read from the DP dual mode adaptor register(s)
* @adapter: I2C adapter for the DDC bus
* @offset: register offset
* @buffer: buffer for return data
* @size: sizo of the buffer
*
* Reads @size bytes from the DP dual mode adaptor registers
* starting at @offset.
*
* Returns:
* 0 on success, negative error code on failure
*/
ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter,
u8 offset, void *buffer, size_t size)
{
struct i2c_msg msgs[] = {
{
.addr = DP_DUAL_MODE_SLAVE_ADDRESS,
.flags = 0,
.len = 1,
.buf = &offset,
},
{
.addr = DP_DUAL_MODE_SLAVE_ADDRESS,
.flags = I2C_M_RD,
.len = size,
.buf = buffer,
},
};
int ret;
ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0)
return ret;
if (ret != ARRAY_SIZE(msgs))
return -EPROTO;
return 0;
}
EXPORT_SYMBOL(drm_dp_dual_mode_read);
/**
* drm_dp_dual_mode_write - Write to the DP dual mode adaptor register(s)
* @adapter: I2C adapter for the DDC bus
* @offset: register offset
* @buffer: buffer for write data
* @size: sizo of the buffer
*
* Writes @size bytes to the DP dual mode adaptor registers
* starting at @offset.
*
* Returns:
* 0 on success, negative error code on failure
*/
ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter,
u8 offset, const void *buffer, size_t size)
{
struct i2c_msg msg = {
.addr = DP_DUAL_MODE_SLAVE_ADDRESS,
.flags = 0,
.len = 1 + size,
.buf = NULL,
};
void *data;
int ret;
data = kmalloc(msg.len, GFP_KERNEL);
if (!data)
return -ENOMEM;
msg.buf = data;
memcpy(data, &offset, 1);
memcpy(data + 1, buffer, size);
ret = i2c_transfer(adapter, &msg, 1);
kfree(data);
if (ret < 0)
return ret;
if (ret != 1)
return -EPROTO;
return 0;
}
EXPORT_SYMBOL(drm_dp_dual_mode_write);
static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN])
{
static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] =
"DP-HDMI ADAPTOR\x04";
return memcmp(hdmi_id, dp_dual_mode_hdmi_id,
sizeof(dp_dual_mode_hdmi_id)) == 0;
}
static bool is_type1_adaptor(uint8_t adaptor_id)
{
return adaptor_id == 0 || adaptor_id == 0xff;
}
static bool is_type2_adaptor(uint8_t adaptor_id)
{
return adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 |
DP_DUAL_MODE_REV_TYPE2);
}
static bool is_lspcon_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN],
const uint8_t adaptor_id)
{
return is_hdmi_adaptor(hdmi_id) &&
(adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 |
DP_DUAL_MODE_TYPE_HAS_DPCD));
}
/**
* drm_dp_dual_mode_detect - Identify the DP dual mode adaptor
* @adapter: I2C adapter for the DDC bus
*
* Attempt to identify the type of the DP dual mode adaptor used.
*
* Note that when the answer is @DRM_DP_DUAL_MODE_UNKNOWN it's not
* certain whether we're dealing with a native HDMI port or
* a type 1 DVI dual mode adaptor. The driver will have to use
* some other hardware/driver specific mechanism to make that
* distinction.
*
* Returns:
* The type of the DP dual mode adaptor used
*/
enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter)
{
char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] = {};
uint8_t adaptor_id = 0x00;
ssize_t ret;
/*
* Let's see if the adaptor is there the by reading the
* HDMI ID registers.
*
* Note that type 1 DVI adaptors are not required to implemnt
* any registers, and that presents a problem for detection.
* If the i2c transfer is nacked, we may or may not be dealing
* with a type 1 DVI adaptor. Some other mechanism of detecting
* the presence of the adaptor is required. One way would be
* to check the state of the CONFIG1 pin, Another method would
* simply require the driver to know whether the port is a DP++
* port or a native HDMI port. Both of these methods are entirely
* hardware/driver specific so we can't deal with them here.
*/
ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_HDMI_ID,
hdmi_id, sizeof(hdmi_id));
DRM_DEBUG_KMS("DP dual mode HDMI ID: %*pE (err %zd)\n",
ret ? 0 : (int)sizeof(hdmi_id), hdmi_id, ret);
if (ret)
return DRM_DP_DUAL_MODE_UNKNOWN;
/*
* Sigh. Some (maybe all?) type 1 adaptors are broken and ack
* the offset but ignore it, and instead they just always return
* data from the start of the HDMI ID buffer. So for a broken
* type 1 HDMI adaptor a single byte read will always give us
* 0x44, and for a type 1 DVI adaptor it should give 0x00
* (assuming it implements any registers). Fortunately neither
* of those values will match the type 2 signature of the
* DP_DUAL_MODE_ADAPTOR_ID register so we can proceed with
* the type 2 adaptor detection safely even in the presence
* of broken type 1 adaptors.
*/
ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_ADAPTOR_ID,
&adaptor_id, sizeof(adaptor_id));
DRM_DEBUG_KMS("DP dual mode adaptor ID: %02x (err %zd)\n",
adaptor_id, ret);
if (ret == 0) {
if (is_lspcon_adaptor(hdmi_id, adaptor_id))
return DRM_DP_DUAL_MODE_LSPCON;
if (is_type2_adaptor(adaptor_id)) {
if (is_hdmi_adaptor(hdmi_id))
return DRM_DP_DUAL_MODE_TYPE2_HDMI;
else
return DRM_DP_DUAL_MODE_TYPE2_DVI;
}
/*
* If neither a proper type 1 ID nor a broken type 1 adaptor
* as described above, assume type 1, but let the user know
* that we may have misdetected the type.
*/
if (!is_type1_adaptor(adaptor_id) && adaptor_id != hdmi_id[0])
DRM_ERROR("Unexpected DP dual mode adaptor ID %02x\n",
adaptor_id);
}
if (is_hdmi_adaptor(hdmi_id))
return DRM_DP_DUAL_MODE_TYPE1_HDMI;
else
return DRM_DP_DUAL_MODE_TYPE1_DVI;
}
EXPORT_SYMBOL(drm_dp_dual_mode_detect);
/**
* drm_dp_dual_mode_max_tmds_clock - Max TMDS clock for DP dual mode adaptor
* @type: DP dual mode adaptor type
* @adapter: I2C adapter for the DDC bus
*
* Determine the max TMDS clock the adaptor supports based on the
* type of the dual mode adaptor and the DP_DUAL_MODE_MAX_TMDS_CLOCK
* register (on type2 adaptors). As some type 1 adaptors have
* problems with registers (see comments in drm_dp_dual_mode_detect())
* we don't read the register on those, instead we simply assume
* a 165 MHz limit based on the specification.
*
* Returns:
* Maximum supported TMDS clock rate for the DP dual mode adaptor in kHz.
*/
int drm_dp_dual_mode_max_tmds_clock(enum drm_dp_dual_mode_type type,
struct i2c_adapter *adapter)
{
uint8_t max_tmds_clock;
ssize_t ret;
/* native HDMI so no limit */
if (type == DRM_DP_DUAL_MODE_NONE)
return 0;
/*
* Type 1 adaptors are limited to 165MHz
* Type 2 adaptors can tells us their limit
*/
if (type < DRM_DP_DUAL_MODE_TYPE2_DVI)
return 165000;
ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_MAX_TMDS_CLOCK,
&max_tmds_clock, sizeof(max_tmds_clock));
if (ret || max_tmds_clock == 0x00 || max_tmds_clock == 0xff) {
DRM_DEBUG_KMS("Failed to query max TMDS clock\n");
return 165000;
}
return max_tmds_clock * 5000 / 2;
}
EXPORT_SYMBOL(drm_dp_dual_mode_max_tmds_clock);
/**
* drm_dp_dual_mode_get_tmds_output - Get the state of the TMDS output buffers in the DP dual mode adaptor
* @type: DP dual mode adaptor type
* @adapter: I2C adapter for the DDC bus
* @enabled: current state of the TMDS output buffers
*
* Get the state of the TMDS output buffers in the adaptor. For
* type2 adaptors this is queried from the DP_DUAL_MODE_TMDS_OEN
* register. As some type 1 adaptors have problems with registers
* (see comments in drm_dp_dual_mode_detect()) we don't read the
* register on those, instead we simply assume that the buffers
* are always enabled.
*
* Returns:
* 0 on success, negative error code on failure
*/
int drm_dp_dual_mode_get_tmds_output(enum drm_dp_dual_mode_type type,
struct i2c_adapter *adapter,
bool *enabled)
{
uint8_t tmds_oen;
ssize_t ret;
if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) {
*enabled = true;
return 0;
}
ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN,
&tmds_oen, sizeof(tmds_oen));
if (ret) {
DRM_DEBUG_KMS("Failed to query state of TMDS output buffers\n");
return ret;
}
*enabled = !(tmds_oen & DP_DUAL_MODE_TMDS_DISABLE);
return 0;
}
EXPORT_SYMBOL(drm_dp_dual_mode_get_tmds_output);
/**
* drm_dp_dual_mode_set_tmds_output - Enable/disable TMDS output buffers in the DP dual mode adaptor
* @type: DP dual mode adaptor type
* @adapter: I2C adapter for the DDC bus
* @enable: enable (as opposed to disable) the TMDS output buffers
*
* Set the state of the TMDS output buffers in the adaptor. For
* type2 this is set via the DP_DUAL_MODE_TMDS_OEN register. As
* some type 1 adaptors have problems with registers (see comments
* in drm_dp_dual_mode_detect()) we avoid touching the register,
* making this function a no-op on type 1 adaptors.
*
* Returns:
* 0 on success, negative error code on failure
*/
int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type,
struct i2c_adapter *adapter, bool enable)
{
uint8_t tmds_oen = enable ? 0 : DP_DUAL_MODE_TMDS_DISABLE;
ssize_t ret;
int retry;
if (type < DRM_DP_DUAL_MODE_TYPE2_DVI)
return 0;
/*
* LSPCON adapters in low-power state may ignore the first write, so
* read back and verify the written value a few times.
*/
for (retry = 0; retry < 3; retry++) {
uint8_t tmp;
ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN,
&tmds_oen, sizeof(tmds_oen));
if (ret) {
DRM_DEBUG_KMS("Failed to %s TMDS output buffers (%d attempts)\n",
enable ? "enable" : "disable",
retry + 1);
return ret;
}
ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN,
&tmp, sizeof(tmp));
if (ret) {
DRM_DEBUG_KMS("I2C read failed during TMDS output buffer %s (%d attempts)\n",
enable ? "enabling" : "disabling",
retry + 1);
return ret;
}
if (tmp == tmds_oen)
return 0;
}
DRM_DEBUG_KMS("I2C write value mismatch during TMDS output buffer %s\n",
enable ? "enabling" : "disabling");
return -EIO;
}
EXPORT_SYMBOL(drm_dp_dual_mode_set_tmds_output);
/**
* drm_dp_get_dual_mode_type_name - Get the name of the DP dual mode adaptor type as a string
* @type: DP dual mode adaptor type
*
* Returns:
* String representation of the DP dual mode adaptor type
*/
const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type)
{
switch (type) {
case DRM_DP_DUAL_MODE_NONE:
return "none";
case DRM_DP_DUAL_MODE_TYPE1_DVI:
return "type 1 DVI";
case DRM_DP_DUAL_MODE_TYPE1_HDMI:
return "type 1 HDMI";
case DRM_DP_DUAL_MODE_TYPE2_DVI:
return "type 2 DVI";
case DRM_DP_DUAL_MODE_TYPE2_HDMI:
return "type 2 HDMI";
case DRM_DP_DUAL_MODE_LSPCON:
return "lspcon";
default:
WARN_ON(type != DRM_DP_DUAL_MODE_UNKNOWN);
return "unknown";
}
}
EXPORT_SYMBOL(drm_dp_get_dual_mode_type_name);
/**
* drm_lspcon_get_mode: Get LSPCON's current mode of operation by
* reading offset (0x80, 0x41)
* @adapter: I2C-over-aux adapter
* @mode: current lspcon mode of operation output variable
*
* Returns:
* 0 on success, sets the current_mode value to appropriate mode
* -error on failure
*/
int drm_lspcon_get_mode(struct i2c_adapter *adapter,
enum drm_lspcon_mode *mode)
{
u8 data;
int ret = 0;
int retry;
if (!mode) {
DRM_ERROR("NULL input\n");
return -EINVAL;
}
/* Read Status: i2c over aux */
for (retry = 0; retry < 6; retry++) {
if (retry)
usleep_range(500, 1000);
ret = drm_dp_dual_mode_read(adapter,
DP_DUAL_MODE_LSPCON_CURRENT_MODE,
&data, sizeof(data));
if (!ret)
break;
}
if (ret < 0) {
DRM_DEBUG_KMS("LSPCON read(0x80, 0x41) failed\n");
return -EFAULT;
}
if (data & DP_DUAL_MODE_LSPCON_MODE_PCON)
*mode = DRM_LSPCON_MODE_PCON;
else
*mode = DRM_LSPCON_MODE_LS;
return 0;
}
EXPORT_SYMBOL(drm_lspcon_get_mode);
/**
* drm_lspcon_set_mode: Change LSPCON's mode of operation by
* writing offset (0x80, 0x40)
* @adapter: I2C-over-aux adapter
* @mode: required mode of operation
*
* Returns:
* 0 on success, -error on failure/timeout
*/
int drm_lspcon_set_mode(struct i2c_adapter *adapter,
enum drm_lspcon_mode mode)
{
u8 data = 0;
int ret;
int time_out = 200;
enum drm_lspcon_mode current_mode;
if (mode == DRM_LSPCON_MODE_PCON)
data = DP_DUAL_MODE_LSPCON_MODE_PCON;
/* Change mode */
ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_LSPCON_MODE_CHANGE,
&data, sizeof(data));
if (ret < 0) {
DRM_ERROR("LSPCON mode change failed\n");
return ret;
}
/*
* Confirm mode change by reading the status bit.
* Sometimes, it takes a while to change the mode,
* so wait and retry until time out or done.
*/
do {
ret = drm_lspcon_get_mode(adapter, &current_mode);
if (ret) {
DRM_ERROR("can't confirm LSPCON mode change\n");
return ret;
} else {
if (current_mode != mode) {
msleep(10);
time_out -= 10;
} else {
DRM_DEBUG_KMS("LSPCON mode changed to %s\n",
mode == DRM_LSPCON_MODE_LS ?
"LS" : "PCON");
return 0;
}
}
} while (time_out);
DRM_ERROR("LSPCON mode change timed out\n");
return -ETIMEDOUT;
}
EXPORT_SYMBOL(drm_lspcon_set_mode);